CN116780606B - AC/DC mixed collection DC series output main wiring system and starting method thereof - Google Patents

AC/DC mixed collection DC series output main wiring system and starting method thereof Download PDF

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Publication number
CN116780606B
CN116780606B CN202311057731.5A CN202311057731A CN116780606B CN 116780606 B CN116780606 B CN 116780606B CN 202311057731 A CN202311057731 A CN 202311057731A CN 116780606 B CN116780606 B CN 116780606B
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China
Prior art keywords
direct current
isolating switch
converter
collection module
converter valve
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CN202311057731.5A
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CN116780606A (en
Inventor
赵峥
李明
徐莹
李探
樊林禛
郑宽
冮明泽
滕尚甫
薛英林
陈琦琛
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State Grid Economic and Technological Research Institute
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State Grid Economic and Technological Research Institute
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/02—Circuit arrangements for ac mains or ac distribution networks using a single network for simultaneous distribution of power at different frequencies; using a single network for simultaneous distribution of ac power and of dc power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/36—Means for starting or stopping converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/125—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M3/135—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
    • H02M3/137—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/145—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M7/155—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
    • H02M7/162—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only in a bridge configuration
    • H02M7/1623—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only in a bridge configuration with control circuit
    • H02M7/1626—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only in a bridge configuration with control circuit with automatic control of the output voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Rectifiers (AREA)

Abstract

The invention belongs to the technical field of flexible direct current transmission, and relates to an alternating current-direct current mixed collection direct current series connection sending-out main wiring system and a starting method thereof, wherein the starting method comprises the following steps: the system comprises an alternating current collection module, a direct current collection module, a mixed direct current collection module and a direct current output module; the alternating current collection module is used for collecting alternating current signals of the near-area new energy station alternating current system; the direct current collection module is used for collecting direct current signals of a direct current system of the remote-area new energy field station; the mixed direct current collection module is used for respectively converting the electric signals in the alternating current collection module and the direct current collection module into direct current signals and collecting the direct current signals in a serial connection mode; and the direct current output module is used for outputting the direct current signals collected by the mixed direct current collection module. Meanwhile, the advantages of the alternating current system in the aspects of short-distance and small-capacity collection and the direct current system in the aspects of long-distance and large-capacity collection are exerted, the conversion links of the collection module and the alternating current collection voltage level are obviously reduced, and the effect of reducing engineering investment is obvious.

Description

AC/DC mixed collection DC series output main wiring system and starting method thereof
Technical Field
The invention relates to an alternating current-direct current mixed collection direct current series connection output main wiring system and a starting method thereof, and belongs to the technical field of flexible direct current transmission.
Background
The built 1 GW-level offshore wind power flexible direct-current engineering and the land new energy direct-current output engineering at home and abroad all adopt an alternating current collection mode. As the capacity of the wind farm is continuously enlarged and the collection distance is further and further increased, the traditional low-voltage alternating-current fundamental frequency collection mode is difficult to meet the technical requirements, and the low-frequency collection or higher-voltage-class alternating-current collection mode can bring about a great increase in investment cost and cannot meet the grid connection requirements of the current new energy flat-price internet age.
Reducing the voltage conversion links of the collection system and reducing the insulation level of the alternating current collection system is a core factor for meeting the economic collection. The low-voltage alternating current collection has better comprehensive performance in the aspect of small-capacity and short-distance new energy collection, and the direct current collection has more technical advantages in the aspect of large-capacity and long-distance new energy collection. For large-capacity long-distance new energy stations, a simple full direct current collection mode can also lead to higher investment cost.
Disclosure of Invention
Aiming at the problems, the invention aims to provide an AC/DC hybrid collection DC serial-connection sending-out main wiring system of a large-scale new energy source with reliability, flexibility and economy and a starting method thereof.
In order to achieve the above purpose, the present invention proposes the following technical solutions: an ac-dc hybrid sink dc serial outgoing main junction system comprising: the system comprises an alternating current collection module, a direct current collection module, a mixed direct current collection module and a direct current output module; the alternating current collection module is used for collecting alternating current signals of the near-area new energy station alternating current system; the direct current collection module is used for collecting direct current signals of a direct current system of the remote-area new energy station; the mixed direct current collection module is used for respectively converting the electric signals in the alternating current collection module and the direct current collection module into direct current signals and collecting the direct current signals in a serial connection mode; the direct current output module is used for outputting the direct current signals collected by the mixed direct current collection module.
Further, the hybrid direct current collection module comprises an alternating current-direct current converter and a direct current-direct current converter, wherein the alternating current-direct current converter is used for converting electric signals of the alternating current collection module, and the direct current-direct current converter is used for converting electric signals of the direct current collection module.
Further, the ac collecting module includes a plurality of ac fans connected in parallel to form the ac system, and collects the power signal of the ac system and converts the power signal into a dc signal through the ac-dc converter.
Further, the direct current collection module comprises a plurality of direct current fans, the direct current fans are connected in series to form the direct current system, and power signals of the direct current system are collected and converted into direct current signals through the direct current-direct current converter.
Further, the ac-dc converter includes a connection transformer, an upper bridge arm reactor, a lower bridge arm reactor, an upper bridge arm converter valve, a lower bridge arm converter valve, a first dc isolating switch and a second dc isolating switch, wherein an input end of the connection transformer is connected with the ac collecting module, an output end of the connection transformer is respectively connected with input ends of the upper bridge arm reactor and the lower bridge arm reactor of each phase, an output end of the upper bridge arm reactor is connected with an input end of the upper bridge arm converter valve, an output end of the lower bridge arm reactor is connected with an input end of the lower bridge arm converter valve, and an output end of the upper bridge arm converter valve is connected with an anode dc bus through the first dc isolating switch or an output end of the lower bridge arm converter valve is connected with a cathode dc bus through the second dc isolating switch.
Further, when the output end of the upper bridge arm converter valve is connected with the positive electrode direct current bus through the first direct current isolating switch, the output end of the lower bridge arm converter valve is connected with the direct-direct current converter through the second direct current isolating switch; when the output end of the lower bridge arm converter valve is connected with the negative electrode direct current bus through the second direct current isolating switch, the output end of the upper bridge arm converter valve is connected with the direct current-direct current converter through the first direct current isolating switch, and the first direct current isolating switch or the second direct current isolating switch is connected with the direct current-direct current converter through the third direct current isolating switch.
Further, a current limiting reactor is arranged between the first direct current isolating switch or the second direct current isolating switch and the direct current bus, the input ends of the first direct current isolating switch and the second direct current isolating switch are connected through a first quick bypass switch, and the output ends of the first direct current isolating switch and the second direct current isolating switch are connected through a fourth direct current isolating switch.
Further, the direct-direct current converter comprises a first direct current capacitor, a direct current reactor, a first thyristor converter valve, a second thyristor converter valve and a soft direct current converter valve; the direct current collection module is connected with the first direct current capacitor in parallel, the positive electrode end of the direct current collection module is connected with a positive electrode bus through the direct current reactor and the first thyristor converter valve in sequence, the negative electrode end of the direct current collection module is connected with a negative electrode bus through the second thyristor converter valve in sequence, and the first thyristor converter valve and the second thyristor converter valve are connected through the flexible direct current converter valve.
Further, the direct-direct current converter further comprises a second direct current capacitor and a third direct current capacitor, one end of the second direct current capacitor is connected with the positive bus, the other end of the second direct current capacitor is grounded, and one end of the third direct current capacitor is connected with the negative bus, and the other end of the third direct current capacitor is grounded; a fifth direct current isolating switch is arranged between the first thyristor converter valve and the positive bus; a sixth direct current isolating switch is arranged between the thyristor converter valve and the negative bus; the input ends of the fifth direct current isolating switch and the sixth direct current isolating switch are connected through a second quick bypass switch, and the output ends of the fifth direct current isolating switch and the sixth direct current isolating switch are connected through a seventh direct current isolating switch.
The invention discloses a starting method of an AC/DC mixed, collected and DC serial-connection sending-out main wiring system, which is used for any one of the AC/DC mixed, collected and DC serial-connection sending-out main wiring system and comprises the following steps: the direct-current voltage UD generated by the station charges the direct-current converter system, so that the remote new energy station is started, and the normal power generation of the remote new energy is realized; charging an AC-DC converter connected with an AC collecting system, and respectively unlocking a positive flexible DC converter valve and a negative flexible DC converter valve to enable the DC port voltage of the converter valve to be 0kV; and starting the near-area new energy source to generate electricity, and adjusting the direct-current port voltage of the flexible converter valve according to the input conditions of the near-area new energy source and the far-area new energy source in the electricity generation process until the direct-current bus voltage rises to the rated voltage Ud.
Due to the adoption of the technical scheme, the invention has the following advantages:
1. The invention provides a large-scale new energy mixing and collecting scheme by an alternating current system and a direct current system, and simultaneously plays the advantages of the alternating current system in the aspects of short-distance, small capacity, long-distance and large capacity collection of the direct current system, thereby obviously reducing the conversion links of the collecting system and the alternating current collecting voltage level and obviously reducing the engineering investment effect.
2. In the scheme of the invention, under normal conditions, the DC-DC converter and the AC-DC converter can be started simultaneously; or the DC-DC converter can be started first and then the AC-DC converter is put into; under the condition of fault or overhaul of a certain type of converter, another type of converter can be independently started, and various operation modes required under large-scale new energy collection can be better adapted.
3. The proposal of the invention can dynamically adapt to the tiny changes of the output of different positions of the same new energy field region by adding a full-bridge submodule with a certain proportion in the AC-DC converter.
In conclusion, the scheme provided by the invention can be widely applied to the field of large-scale new energy direct current transmission.
Drawings
FIG. 1 is a schematic diagram of an AC/DC hybrid junction DC serial outgoing main wiring system according to an embodiment of the present invention;
Fig. 2 is a schematic structural diagram of a hybrid dc sink module according to an embodiment of the invention.
Detailed Description
The invention is depicted in detail by specific examples in order to provide a better understanding of the technical solution of the invention to those skilled in the art. It should be understood, however, that the detailed description is presented only to provide a better understanding of the invention, and should not be taken to limit the invention. In the description of the present invention, it is to be understood that the terminology used is for the purpose of description only and is not to be interpreted as indicating or implying relative importance.
In order to solve the problems that the low-voltage alternating current collection in the prior art has better comprehensive performance in the aspects of small-capacity and short-distance new energy collection, the direct current collection has more technical advantages in the aspects of large-capacity and long-distance new energy collection, and the high investment cost is caused by adopting a full direct current collection mode for a large-capacity and long-distance new energy station, the invention provides an alternating current-direct current mixed collection direct current serial-connection sending-out main wiring system and a starting method thereof, the new energy station is divided according to the grid-connected distance, the traditional alternating current collection mode is adopted at a relatively short distance, and the technical advantages of the two collection modes can be exerted to the greatest extent by adopting the direct current collection mode at a relatively long distance, and the whole investment is optimal; on the other hand, the two collecting modules are respectively converted into high-voltage direct current with the same voltage level through an alternating-direct converter and a direct-direct converter at the sending-out side, and then power is integrally sent out in a serial connection mode; meanwhile, when one collecting module or the corresponding converter fails, the other collecting and sending system can normally operate. The invention will now be described in more detail by way of example with reference to the accompanying drawings.
Example 1
The embodiment discloses a main wiring system for series connection and sending of mixed direct current and mixed direct current of alternating current and direct current, as shown in fig. 1, comprising: the system comprises an alternating current collection module, a direct current collection module, a mixed direct current collection module and a direct current output module;
The alternating current collection module is used for collecting alternating current signals of the near-area new energy station alternating current system; the alternating current collection module comprises a plurality of alternating current fans of the near-area new energy field station, the alternating current fans are connected in parallel to form an alternating current system, and the voltage is U1 to collect power signals of the alternating current system.
The direct current collection module is used for collecting direct current signals of a direct current system of the remote-area new energy field station; the direct current collection module comprises a plurality of direct current fans which are connected in series to form a direct current system with the voltage of 2Ua, and power signals of the direct current system are collected.
The mixed direct current collection module comprises an alternating current-direct current converter and a direct current-direct current converter, wherein the alternating current-direct current converter is used for converting electric signals of the alternating current collection module, so that power signals of an alternating current system collected by the voltage U1 in the alternating current collection module are converted into direct current signals through the alternating current-direct current converter; the DC-DC converter is used for converting the electric signals of the DC collecting module, so that the power signals of the DC system collected by the voltage of 2Ua in the DC collecting module are converted into DC signals through the DC-DC converter. And the mixed direct current collection module is used for respectively converting the electric signals in the alternating current collection module and the direct current collection module into direct current signals, and collecting the direct current signals in a serial connection mode to form voltage 2Ud.
And the direct current output module is used for outputting the direct current signals collected by the mixed direct current collection module.
The direct current collection module and the direct current output module both adopt symmetrical monopole topological structures.
The AC-DC converter comprises a connecting transformer, an upper bridge arm reactor, a lower bridge arm reactor, an upper bridge arm converter valve, a lower bridge arm converter valve, a first DC isolating switch and a second DC isolating switch, wherein the input end of the connecting transformer is connected with an AC collecting module, the output end of the connecting transformer is respectively connected with the input ends of the upper bridge arm reactor and the lower bridge arm reactor of each phase, the output end of the upper bridge arm reactor is connected with the input end of the upper bridge arm converter valve, the output end of the lower bridge arm reactor is connected with the input end of the lower bridge arm converter valve, and the output end of the upper bridge arm converter valve is connected with an anode DC bus through the first DC isolating switch or the output end of the lower bridge arm converter valve is connected with a cathode DC bus through the second DC isolating switch. That is, the number of the ac-dc converters provided in this embodiment may be plural, where the output end of the upper bridge arm converter valve of one ac-dc converter is connected to the positive dc bus through the first dc isolating switch, and the output end of the other lower bridge arm converter valve is connected to the negative dc bus through the second dc isolating switch. When the output end of the upper bridge arm converter valve is connected with the positive DC bus through the first DC isolating switch, the output end of the lower bridge arm converter valve is connected with the DC-DC converter through the second DC isolating switch; when the output end of the lower bridge arm converter valve is connected with the negative electrode direct current bus through the second direct current isolating switch, the output end of the upper bridge arm converter valve is connected with the direct-direct current converter through the first direct current isolating switch, and the first direct current isolating switch or the second direct current isolating switch is connected with the direct-direct current converter through the third direct current isolating switch. A current limiting reactor is arranged between the first direct current isolating switch or the second direct current isolating switch and the direct current bus, the input ends of the first direct current isolating switch and the second direct current isolating switch are connected through a first rapid bypass switch, and the output ends of the first direct current isolating switch and the second direct current isolating switch are connected through a fourth direct current isolating switch. In this embodiment, the upper bridge arm converter valve and the lower bridge arm converter valve are formed by a half-bridge submodule HBSM, a full-bridge submodule FBSM or a combination of the half-bridge submodule HBSM and the full-bridge submodule FBSM, and the number of the half-bridge submodule HBSM and the full-bridge submodule FBSM is specifically set and determined according to actual needs. The half-bridge submodule HBSM consists of two submodules and a capacitor, wherein the two submodules are connected in series and connected with one capacitor in parallel, and the submodules consist of a field effect transistor and a diode which are connected in parallel. The full-bridge submodule HBSM is composed of four submodules and a capacitor, the first submodule is connected with the second submodule in series, the third submodule is connected with the fourth submodule in series, and the first submodule and the second submodule are connected with the third submodule, the fourth submodule and the capacitor in parallel.
As shown in fig. 2, in this embodiment, the number of ac-dc converters is two, that is, the positive near-area ac collection module and the negative near-area ac collection module, and the specific number of ac-dc converters may be determined according to the number of specific ac collection modules. The alternating current sides of the positive near-area alternating current collection module and the negative near-area alternating current collection module can be connected through an alternating current circuit, and can be respectively connected with an alternating current-direct current converter.
The topological structure of the AC-DC converter connected with the AC collection module in the near zone of the positive electrode is shown in figure 2, the network side of the connecting transformer T1 (three phases a, b and c) is connected with the AC collection system, the valve side is respectively connected with one end of an upper bridge arm and a lower bridge arm reactor L0 (three phases a, b and c) in the near zone of the positive electrode, the other ends of the upper bridge arm and the lower bridge arm reactor L0 (three phases a, b and c) are respectively connected with one end of a converter valve of the bridge arm, the three phases of the upper bridge arm converter valve are collected and then are connected with one end of a DC isolating switch Q11, the other end of the DC isolating switch Q11 is connected with one end of a positive electrode current limiting reactor L2, the other end of the positive electrode current limiting reactor L2 is connected with a positive electrode DC bus, the three phases of the lower bridge arm converter valve are collected and then are connected with one end of a DC isolating switch Q13, and the other end of the DC isolating switch Q13 is connected with the positive electrode bus of the DC-DC converter through a DC isolating switch Q44; one end of the quick bypass switch Q1 is connected with a connecting point of the direct current isolating switch Q11 after three phases of the upper bridge arm converter valve are converged, and the other end of the quick bypass switch Q1 is connected with a connecting point of the direct current isolating switch Q13 after three phases of the lower bridge arm converter valve are converged; one end of the direct current isolating switch Q12 is connected with a connecting point of the direct current isolating switch Q11 and the positive current limiting reactor L2, and the other end of the direct current isolating switch Q12 is connected with a connecting point of the direct current isolating switch Q13 and the direct current isolating switch Q44.
The topological structure of the AC-DC converter connected with the AC collecting module in the near positive zone is shown in figure 2, the network side of the connecting transformer T2 (three phases a, b and c) is connected with the AC collecting system, the valve side is respectively connected with one ends of an upper bridge arm and a lower bridge arm reactor L0 (three phases a, b and c) in the near negative zone, the other ends of the upper bridge arm and the lower bridge arm reactor L0 (three phases a, b and c) are respectively connected with a converter valve of the bridge arm, the three phases of the lower bridge arm converter valve are collected and then are connected with one end of a DC isolating switch Q33, the other end of the DC isolating switch Q33 is connected with one end of a negative current limiting reactor L2, the other end of the negative current limiting reactor L2 is connected with a negative DC bus, and the other end of the DC isolating switch Q31 is connected with the negative bus of the DC-DC converter through a DC isolating switch Q55 after the three phases of the upper bridge arm are collected; one end of the fast bypass switch Q3 is connected with the connection point of the direct current isolating switch Q33 after three phases of the lower bridge arm converter valve are collected; one end of the direct current isolating switch Q32 is connected with a connecting point of the direct current isolating switch Q33 and the negative current limiting reactor L2, and the other end of the direct current isolating switch Q32 is connected with a connecting point of the direct current isolating switch Q31 and the direct current isolating switch Q55.
The direct-direct current converter comprises a first direct current capacitor, a direct current reactor, a first thyristor converter valve, a second thyristor converter valve and a soft direct current converter valve; the direct current collection module is connected with the first direct current capacitor in parallel, the positive electrode end of the direct current collection module is connected with the positive electrode bus through the direct current reactor and the first thyristor converter valve in sequence, the negative electrode end of the direct current collection module is connected with the negative electrode bus through the second thyristor converter valve in sequence, and the first thyristor converter valve and the second thyristor converter valve are connected through the flexible direct current converter valve. The direct-direct converter further comprises a second direct-current capacitor and a third direct-current capacitor, one end of the second direct-current capacitor is connected with the positive bus, the other end of the second direct-current capacitor is grounded, and one end of the third direct-current capacitor is connected with the negative bus, and the other end of the third direct-current capacitor is grounded; a fifth direct current isolating switch is arranged between the first thyristor converter valve and the positive bus; a sixth direct current isolating switch is arranged between the thyristor converter valve and the negative bus; the input ends of the fifth direct current isolating switch and the sixth direct current isolating switch are connected through the second rapid bypass switch, and the output ends of the fifth direct current isolating switch and the sixth direct current isolating switch are connected through the seventh direct current isolating switch.
Specifically, as shown in fig. 2, one side of a direct current capacitor C1 of the direct current-direct current converter is connected in parallel with a direct current collecting system, the positive electrode of the collecting system is connected with one end of L1, the positive electrode side of the collecting system is connected with one end of L1, the other end of L1 is connected with one end of a soft direct current converter valve V1, the other end of the soft direct current converter valve is connected with the negative electrode side of C1, the positive electrode end of the parallel system is connected with one end of a thyristor converter valve DX, the other end of DX is connected with a positive electrode bus bar at the output side of the direct current-direct current converter, the negative electrode end of the direct current collecting system is connected with one end of the thyristor converter valve DY, the other end of DY is connected with a negative electrode bus bar at the output side of the direct current-direct current converter, one end of the capacitor C2 is connected to a positive electrode bus of the DC-DC converter on the delivery side, the other end of the capacitor C2 is grounded, the positive electrode bus of the DC-DC converter on the delivery side is connected with one end of the DC isolating switch Q21, the other end of the DC isolating switch Q21 is connected with the negative electrode of the AC-DC converter on the positive electrode near zone through the DC isolating switch Q44, one end of the capacitor C3 is connected to a negative electrode bus of the DC-DC converter on the delivery side, the other end of the capacitor C3 is grounded, the negative electrode bus of the DC-DC converter on the delivery side is connected with one end of the DC isolating switch Q23, and the other end of the DC isolating switch Q23 is connected with the positive electrode of the AC-DC converter on the negative electrode near zone through the DC isolating switch Q55. One end of the quick bypass switch Q2 is connected with a connecting point of the direct current capacitor C2 and the direct current isolating switch Q21, and the other end of the quick bypass switch Q2 is connected with a connecting point of the direct current capacitor C3 and the direct current isolating switch Q23; one end of the direct current isolating switch Q22 is connected with a connecting point of the direct current isolating switch Q21 and the direct current isolating switch Q44, and the other end of the direct current isolating switch Q22 is connected with a connecting point of the direct current isolating switch Q23 and the direct current isolating switch Q55. In this embodiment, the thyristor converter valve DX and the thyristor converter valve DY each include a plurality of diodes connected in series, and the soft direct current converter valve V1 includes a plurality of submodules connected in series.
In a preferred embodiment, the rated dc currents of the two ac-dc converters and the dc-dc converter are the same, and are Id, the ratio of the power of the two ac collecting systems to the power of the dc collecting system is (Ud-Ud)/Ud, and considering that a certain output deviation ±k% exists in the new energy resources of the near zone and the far zone (calculated based on the per unit value of the output of each wind field), each bridge arm of the soft dc converter valve is additionally provided with a full bridge sub-module FBSM of k% of the sum of the above numbers on the basis that the half bridge sub-module HBSM and the full bridge sub-module FBSM can produce the rated dc voltage, so as to adjust the output deviation of each wind field and avoid the inconsistency of the dc currents of the 3 series converters. In addition, in order to realize normal starting of the direct-direct converter and the alternating-direct converter, the proportion of the full-bridge submodule FBSM to the bridge arm submodule is not lower than 50%.
Example two
Based on the same inventive concept, the embodiment discloses a starting method of an ac/dc hybrid collection dc serial-delivery main wiring system, which is used for any one of the above ac/dc hybrid collection dc serial-delivery main wiring systems, and comprises the following steps:
closing a direct current isolating switch Q21 and a direct current isolating switch Q23, opening the direct current isolating switch Q22 and rapidly bypassing the switch Q2, and charging a direct current-direct current converter system by a direct current voltage UD generated by a station, so as to start a remote new energy field station and realize normal power generation and output of the remote new energy;
the power utilization system of the integrated station is utilized to charge an alternating current-direct current converter connected with the alternating current collecting module through a connection transformer T1 and a connection transformer T2, and a positive flexible direct current converter valve and a negative flexible direct current converter valve are unlocked respectively, so that the voltage of a direct current port of the converter valve is 0kV;
Closing the direct current isolating switch Q11, the direct current isolating switch Q13, the direct current isolating switch Q31 and the direct current isolating switch Q33, opening the direct current isolating switch Q12 and the direct current isolating switch Q32, and opening the quick bypass switch Q1 and the quick bypass switch Q3;
And starting the near-area new energy source to generate electricity, and adjusting the direct-current port voltage of the flexible converter valve according to the input conditions of the near-area new energy source and the far-area new energy source in the electricity generation process until the direct-current bus voltage rises to the rated voltage Ud.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical aspects of the present application and not for limiting the same, and although the present application has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that: modifications and equivalents may be made to the specific embodiments of the application without departing from the spirit and scope of the application, which is intended to be covered by the claims. The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily appreciate variations or alternatives within the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims (9)

1. An ac/dc hybrid sink dc serial delivery main junction system comprising: the system comprises an alternating current collection module, a direct current collection module, a mixed direct current collection module and a direct current output module;
the alternating current collection module is used for collecting alternating current signals of the near-area new energy station alternating current system;
The direct current collection module is used for collecting direct current signals of a direct current system of the remote-area new energy station;
The mixed direct current collection module is used for respectively converting the electric signals in the alternating current collection module and the direct current collection module into direct current signals and collecting the direct current signals in a serial connection mode;
the direct current output module is used for outputting the direct current signals collected by the mixed direct current collection module;
The mixed direct current collection module comprises an alternating current-direct current converter and a direct current-direct current converter, wherein the alternating current-direct current converter is used for converting electric signals of the alternating current collection module, and the direct current-direct current converter is used for converting electric signals of the direct current collection module;
The direct-direct converter and the alternating-direct converter are started simultaneously; or firstly starting the DC-DC converter and then putting the AC-DC converter into the DC-DC converter; or in the event of a failure or service of one of the converters, the other converter is started up alone.
2. The ac/dc hybrid junction dc serial outgoing main junction system of claim 1, wherein the ac junction module comprises a plurality of ac fans connected in parallel to form the ac system, and wherein the ac system power signal is collected and converted to a dc signal by the ac-dc converter.
3. The ac/dc hybrid junction dc serial outgoing main junction system of claim 1, wherein said dc junction module comprises a plurality of dc fans connected in series to form said dc system, and wherein power signals of said dc system are collected and converted to dc signals by said dc-dc converter.
4. The ac-dc hybrid junction dc serial outgoing main wiring system of claim 1, wherein the ac-dc converter comprises a connection transformer, an upper bridge arm reactor, a lower bridge arm reactor, an upper bridge arm converter valve, a lower bridge arm converter valve, a first dc isolating switch and a second dc isolating switch, the input end of the connection transformer is connected to the ac junction module, the output end of the connection transformer is connected to the input ends of the upper bridge arm reactor and the lower bridge arm reactor of each phase respectively, the output end of the upper bridge arm reactor is connected to the input end of the upper bridge arm converter valve, the output end of the lower bridge arm reactor is connected to the input end of the lower bridge arm converter valve, and the output end of the upper bridge arm converter valve is connected to the positive dc bus through the first dc isolating switch or the output end of the lower bridge arm converter valve is connected to the negative dc bus through the second dc isolating switch.
5. The ac/dc hybrid junction dc serial outgoing main wiring system of claim 4, characterized in that when the output end of the upper bridge arm converter valve is connected to the positive dc bus through the first dc isolating switch, the output end of the lower bridge arm converter valve is connected to the dc-dc converter through the second dc isolating switch; when the output end of the lower bridge arm converter valve is connected with the negative electrode direct current bus through the second direct current isolating switch, the output end of the upper bridge arm converter valve is connected with the direct current-direct current converter through the first direct current isolating switch, and the first direct current isolating switch or the second direct current isolating switch is connected with the direct current-direct current converter through the third direct current isolating switch.
6. The ac/dc hybrid sink dc serial outgoing main junction system of claim 4, characterized in that a current limiting reactor is disposed between the first dc isolating switch or the second dc isolating switch and the dc bus, input ends of the first dc isolating switch and the second dc isolating switch are connected through a first fast bypass switch, and output ends of the first dc isolating switch and the second dc isolating switch are connected through a fourth dc isolating switch.
7. The ac/dc hybrid junction dc serial outgoing main junction system of claim 1, wherein said dc-dc converter comprises a first dc capacitor, a dc reactor, a first thyristor converter valve, a second thyristor converter valve, and a soft dc converter valve;
The direct current collection module is connected with the first direct current capacitor in parallel, the positive electrode end of the direct current collection module is connected with a positive electrode bus through the direct current reactor and the first thyristor converter valve in sequence, the negative electrode end of the direct current collection module is connected with a negative electrode bus through the second thyristor converter valve in sequence, and the first thyristor converter valve and the second thyristor converter valve are connected through the flexible direct current converter valve.
8. The ac/dc hybrid junction dc serial outgoing main wiring system of claim 7, wherein said dc-dc converter further comprises a second dc capacitor and a third dc capacitor, said second dc capacitor having one end connected to said positive bus and the other end grounded, and said third dc capacitor having one end connected to said negative bus and the other end grounded; a fifth direct current isolating switch is arranged between the first thyristor converter valve and the positive bus; a sixth direct current isolating switch is arranged between the thyristor converter valve and the negative bus; the input ends of the fifth direct current isolating switch and the sixth direct current isolating switch are connected through a second quick bypass switch, and the output ends of the fifth direct current isolating switch and the sixth direct current isolating switch are connected through a seventh direct current isolating switch.
9. A method for starting an ac/dc hybrid sink dc serial delivery main junction system according to any one of claims 1 to 8, comprising the steps of:
The direct-current voltage UD generated by the station charges the direct-current converter system, so that the remote new energy station is started, and the normal power generation of the remote new energy is realized;
charging an AC-DC converter connected with the AC collection module, and respectively unlocking the positive flexible DC converter valve and the negative flexible DC converter valve to enable the DC port voltage of the converter valve to be 0kV;
And starting the near-area new energy source to generate electricity, and adjusting the direct-current port voltage of the flexible converter valve according to the input conditions of the near-area new energy source and the far-area new energy source in the electricity generation process until the direct-current bus voltage rises to the rated voltage Ud.
CN202311057731.5A 2023-08-22 2023-08-22 AC/DC mixed collection DC series output main wiring system and starting method thereof Active CN116780606B (en)

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